<template>
	<div class="upload-file">
		<el-upload
			multiple
			:action="uploadFileUrl"
			:before-upload="handleBeforeUpload"
			:file-list="fileList"
			:limit="limit"
			:on-error="handleUploadError"
			:on-exceed="handleExceed"
			:on-success="handleUploadSuccess"
			:show-file-list="false"
			:headers="headers"
			class="upload-file-uploader"
			ref="fileUpload">
			<!-- 上传按钮 -->
			<el-button plain icon="el-icon-upload" type="primary">选取文件</el-button>
			<!-- 上传提示 -->
			<div class="el-upload__tip" slot="tip" v-if="showTip">
				请上传
				<template v-if="fileSize">
					大小不超过
					<b style="color: #f56c6c">{{ fileSize }}MB</b>
				</template>
				<template v-if="fileType">
					格式为
					<b style="color: #f56c6c">{{ fileType.join('/') }}</b>
				</template>
				的文件
			</div>
		</el-upload>

		<!-- 文件列表 -->
		<transition-group
			class="upload-file-list el-upload-list el-upload-list--text"
			name="el-fade-in-linear"
			tag="ul">
			<li
				:key="file.url"
				class="el-upload-list__item ele-upload-list__item-content"
				v-for="(file, index) in fileList">
				<el-link :href="`${file.url}`" :underline="false" target="_blank">
					<span class="el-icon-document">{{ getFileName(file.name) }}</span>
				</el-link>
				<div class="ele-upload-list__item-content-action">
					<el-link :underline="false" @click="handleDelete(index)" type="danger">
						删除
					</el-link>
				</div>
			</li>
		</transition-group>
	</div>
</template>

<script>
	import { getToken } from '@/utils/auth';
	import { listByIds, delOss } from '@/api/system/oss';

	export default {
		name: 'FileUpload',
		props: {
			// 值
			value: [String, Object, Array],
			// 数量限制
			limit: {
				type: Number,
				default: 5,
			},
			// 大小限制(MB)
			fileSize: {
				type: Number,
				default: 5,
			},
			// 文件类型, 例如['png', 'jpg', 'jpeg']
			fileType: {
				type: Array,
				default: () => ['doc', 'xls', 'ppt', 'txt', 'pdf'],
			},
			// 是否显示提示
			isShowTip: {
				type: Boolean,
				default: false,
			},
		},
		data() {
			return {
				number: 0,
				uploadList: [],
				baseUrl: process.env.VUE_APP_BASE_API,
				uploadFileUrl: process.env.VUE_APP_BASE_API + '/system/oss/upload', // 上传文件服务器地址
				headers: {
					Authorization: 'Bearer ' + getToken(),
				},
				fileList: [],
			};
		},
		watch: {
			value: {
				async handler(val) {
					if (val) {
						let temp = 1;
						// 首先将值转为数组
						let list;
						if (Array.isArray(val)) {
							list = val;
						} else {
							await listByIds(val).then(res => {
								list = res.data.map(oss => {
									oss = {
										name: oss.originalName,
										url: oss.url,
										ossId: oss.ossId,
									};
									return oss;
								});
							});
						}
						// 然后将数组转为对象数组
						this.fileList = list.map(item => {
							item = { name: item.name, url: item.url, ossId: item.ossId };
							item.uid = item.uid || new Date().getTime() + temp++;
							return item;
						});
					} else {
						this.fileList = [];
						return [];
					}
				},
				deep: true,
				immediate: true,
			},
		},
		computed: {
			// 是否显示提示
			showTip() {
				return this.isShowTip && (this.fileType || this.fileSize);
			},
		},
		methods: {
			// 上传前校检格式和大小
			handleBeforeUpload(file) {
				// 校检文件类型
				if (this.fileType) {
					const fileName = file.name.split('.');
					const fileExt = fileName[fileName.length - 1];
					const isTypeOk = this.fileType.indexOf(fileExt) >= 0;
					if (!isTypeOk) {
						this.$modal.msgError(
							`文件格式不正确, 请上传${this.fileType.join('/')}格式文件!`,
						);
						return false;
					}
				}
				// 校检文件大小
				if (this.fileSize) {
					const isLt = file.size / 1024 / 1024 < this.fileSize;
					if (!isLt) {
						this.$modal.msgError(`上传文件大小不能超过 ${this.fileSize} MB!`);
						return false;
					}
				}
				this.$modal.loading('正在上传文件，请稍候...');
				this.number++;
				return true;
			},
			// 文件个数超出
			handleExceed() {
				this.$modal.msgError(`上传文件数量不能超过 ${this.limit} 个!`);
			},
			// 上传失败
			handleUploadError(err) {
				this.$modal.msgError('上传文件失败，请重试');
				this.$modal.closeLoading();
			},
			// 上传成功回调
			handleUploadSuccess(res, file) {
				if (res.code === 200) {
					this.uploadList.push({
						name: res.data.fileName,
						url: res.data.url,
						ossId: res.data.ossId,
					});
					this.uploadedSuccessfully();
				} else {
					this.number--;
					this.$modal.closeLoading();
					this.$modal.msgError(res.msg);
					this.$refs.fileUpload.handleRemove(file);
					this.uploadedSuccessfully();
				}
			},
			// 删除文件
			handleDelete(index) {
				let ossId = this.fileList[index].ossId;
				delOss(ossId);
				this.fileList.splice(index, 1);
				this.$emit('input', this.listToString(this.fileList));
			},
			// 上传结束处理
			uploadedSuccessfully() {
				if (this.number > 0 && this.uploadList.length === this.number) {
					this.fileList = this.fileList.concat(this.uploadList);
					this.uploadList = [];
					this.number = 0;
					this.$emit('input', this.listToString(this.fileList));
					this.$modal.closeLoading();
				}
			},
			// 获取文件名称
			getFileName(name) {
				// 如果是url那么取最后的名字 如果不是直接返回
				if (name.lastIndexOf('/') > -1) {
					return name.slice(name.lastIndexOf('/') + 1);
				} else {
					return name;
				}
			},
			// 对象转成指定字符串分隔
			listToString(list, separator) {
				let strs = '';
				separator = separator || ',';
				for (let i in list) {
					strs += list[i].ossId + separator;
				}
				return strs != '' ? strs.substr(0, strs.length - 1) : '';
			},
		},
	};
</script>

<style scoped lang="scss">
	@import '~@/assets/styles/variables.scss';
	.upload-file-uploader {
		margin-bottom: 5px;
	}
	.upload-file-list .el-upload-list__item {
		border: 1px solid #e4e7ed;
		line-height: 2;
		margin-bottom: 10px;
		position: relative;
	}
	.upload-file-list .ele-upload-list__item-content {
		display: flex;
		justify-content: space-between;
		align-items: center;
		color: inherit;
	}
	.ele-upload-list__item-content-action {
		width: 50px;
		text-align: center;
	}
	.ele-upload-list__item-content-action .el-link {
		margin-right: 10px;
	}

	.el-upload__tip {
		font-size: 12px;
		color: $black99;
		line-height: 17px;
	}
</style>
